WO1999027360A1

WO1999027360A1 - Method and device for diagnosing deterioration of an article having at least a covering layer of organic polymer material

Info

Publication number: WO1999027360A1
Application number: PCT/JP1998/005194
Authority: WO
Inventors: Tetsuya Ashida; Tsuyoshi Ikeda; Junichiro Ikehara; Masanori Fujii; Hiroshi Ishibashi; Yoshiro Habuka; Minoru Okamoto; Eiji Onuma; Hiroshi Kato
Original assignee: Mitsubishi Cable Industries, Ltd.; Kato, Kazuko
Priority date: 1997-11-21
Filing date: 1998-11-18
Publication date: 1999-06-03
Also published as: US6450036B1

Abstract

A method of diagnosing the deterioration of a covering layer of organic polymer material, comprising first measuring the deterioration diagnostic characteristic and the corresponding ultrasonic wave propagation characteristic of a sample of the covering layer, these measured values preparing a set of data including the correlated measured values. The ultrasonic wave propagation characteristic of an actual covering layer is measured by propagating ultrasonic waves along or near the surface of the actual covering layer by means of ultrasonic wave transmission and reception means through a delay chip. The deterioration diagnostic characteristic corresponding to the measured propagation characteristic is determined from the data set. By adding elements of time elapse to the data set, it is also possible to predict the remaining longevity of the covering layer.

Description

TECHNICAL FIELD A method for diagnosing deterioration of an article having at least a coating layer made of an organic polymer material and an apparatus therefor

The present invention relates to a method for diagnosing deterioration of an article (typically, a cable) having at least a coating layer made of an organic polymer material and an apparatus therefor.

Background art

Since the insulation layer of the laid cable (insulator layer made of organic polymer material) changes over time due to various factors and the electrical insulation deteriorates, it is necessary to periodically inspect and diagnose the deterioration state. is there. Therefore, various degradation diagnosis methods have been proposed. Among them, the method of diagnosing the deterioration state by propagating ultrasonic waves (JP-A-7-35732, JP-A-7-35733) does not require breaking the cable. It is excellent in a point. According to the method described in this publication, an ultrasonic wave is propagated through a coating layer of a laid cable to calculate an ultrasonic wave propagation velocity, which is converted into physical properties such as elongation at break and hardness of the coating layer. Diagnosis of deterioration state is performed by characteristics.

The method of measuring the propagation velocity using ultrasonic waves in the above-mentioned publication is schematically described. Ultrasonic waves are incident from the surface of the cable coating layer toward the center of the cable, and the ultrasonic waves are applied to the coating layer and the layer below it. For example, the time t required to reflect at the interface with the conductor) and return to the incident position again is measured, and from this t and the thickness a of the coating layer, V = 2 a Z t is calculated, The value of V is defined as the propagation speed of the ultrasonic wave in the coating layer.

However, the measurement method in the above publication has a problem in that the thickness a of the coating layer is used for calculating the propagation velocity V of the ultrasonic wave. In other words, the above measurement method is useful when the value of the thickness a of the coating layer can be known with high precision, but the value of a can be accurately determined for indestructible objects such as laid cables. It is difficult to get. For example, by referring to a design specification or the like, a design reference dimension of the value of a can be obtained. However, when manufacturing insulated wires, manufacturing tolerances of ± 15% with respect to the design reference dimensions are allowed, so the difference from the actual value of a may be large. Therefore, the propagation velocity calculated using a obtained nondestructively and the deterioration diagnosis based on it were of low accuracy.

An object of the present invention is to provide a more preferable deterioration diagnosis method for diagnosing the degree of deterioration of an article (for example, a cable) having at least a coating layer made of an organic polymer material by using ultrasonic waves. An object of the present invention is to provide a preferable deterioration diagnosis apparatus for performing the method. Disclosure of the invention

The deterioration diagnosis method of the present invention is a method for diagnosing deterioration of an article having at least a coating layer made of an organic polymer material, and includes a method of diagnosing deterioration of a coating layer sample and corresponding ultrasonic propagation characteristics. By measuring the values of the deterioration diagnosis characteristics and the ultrasonic propagation characteristics, a data group for deterioration diagnosis is created, and ultrasonic waves are propagated to the surface of the coating layer of the article and the vicinity of the surface, whereby the coating is formed. Measuring the ultrasonic wave propagation characteristics of the layer and obtaining a corresponding deterioration diagnosis characteristic from the data group. The deterioration diagnosis method according to the present invention comprises the steps of: A material consisting of one or more elements selected from the type of molecular material, the type of plasticizer mixed in the organic polymer material, the amount of plasticizer, the amount of filler, and the amount of carbon Finish The deterioration diagnosis characteristics and the corresponding ultrasonic propagation characteristics are measured for each sample having a different material specification, and a data group for deterioration diagnosis is created, and the ultrasonic propagation characteristics of the coating layer of the article are measured. The measurement is performed to determine the deterioration diagnostic characteristics corresponding to the ultrasonic wave propagation characteristics from the data group of the material specification, which is equal to the coating layer.

In the deterioration diagnosis method according to the present invention, the ultrasonic wave propagation characteristic is an ultrasonic wave propagation velocity, and the method of measuring the propagation velocity comprises: an ultrasonic transmission unit and an ultrasonic reception unit; The ultrasonic wave transmitted from the transmitting means is installed on the surface of the measuring object via a laser chip, and the ultrasonic wave is linearly propagated in the measuring object to the installation position of the receiving means and can be received by the receiving means. The propagation times t 1 and t 2 of the respective ultrasonic waves are measured when the installation interval between the transmitting means and the receiving means is L 1 and L 2, and (L 2 — L l) Z (t 2 — t 1 ) Is a method of measuring the propagation velocity of the ultrasonic wave.

In the deterioration diagnosis method of the present invention, the ultrasonic wave propagation characteristic is a propagation time of the ultrasonic wave when the ultrasonic wave propagates over a specific distance, the ultrasonic wave transmitting means and the ultrasonic wave The receiving means is installed at the specified distance on the surface of the inspection object via the delay chip, and the ultrasonic wave transmitted from the transmission means linearly moves through the inspection object to the installation position of the reception means. The propagation time is measured by measuring the time from propagation to reception by the receiving means via the delay chip.

The deterioration diagnosis method according to the present invention is directed to a cable in which the article is laid, and how the deterioration factors that deteriorate the coating layer of the cable are distributed along the longitudinal direction of the cable. This is to determine whether the deterioration factor is high and to perform a deterioration diagnosis on the parts where the degree of deterioration is large.

In the deterioration diagnosis method of the present invention, the value of the above-mentioned deterioration diagnosis characteristic obtained for the coating layer of the article is defined as E 1, and the value of the deterioration diagnosis characteristic is used for a sample of the same material as the coating layer. The heating temperature t and the corresponding heating time h corresponding to each value of the deterioration diagnosis characteristics when the values are changed including the above are measured to obtain a data group for remaining life estimation, and this data group for remaining life estimation is obtained. The heating period t1 corresponding to the heating time h1 at the value E1 of the deterioration diagnosis characteristic is obtained by regarding the use period of the article as the heating time h1 using the above, and the use limit value E of the deterioration diagnosis characteristic is obtained. The heating time hz corresponding to the heating temperature t1 at z is determined, and the value of hz-h1 is used as the remaining life.

The deterioration diagnosis device of the present invention is a device for diagnosing deterioration of an article having at least a coating layer made of an organic polymer material, and has at least the following measurement device (A).

(A) Ultrasonic propagation characteristics of the coating layer of the article or the sample of the coating layer as the measurement object A measuring device, comprising: an ultrasonic transmitting means, an ultrasonic receiving means, a delay chip (A 1) interposed between the ultrasonic wave transmitting means, the ultrasonic receiving means, and the ultrasonic wave when the ultrasonic wave transmitting means A propagation time measuring means for measuring a time from transmission from the means to reception by the receiving means.

(A1) When the ultrasonic wave enters the measuring object from the delay chip, the tilt angle and the material are set so that the propagation direction of the ultrasonic wave changes and the ultrasonic wave propagates on and near the surface of the measuring object. The delay chip that is selected. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an example of a deterioration diagnosis device of the present invention, and is a diagram showing a state used for deterioration diagnosis of a cable. The illustration of the driving device and the like is omitted.

FIG. 2 is a diagram for explaining the configuration of the delay chip.

FIG. 3 is a diagram showing a configuration example of the entire deterioration diagnosis device of the present invention. An example of a drive system, a control system, and an arithmetic system is shown in a block diagram.

FIG. 4 is a group of graphs showing the relationship between the heating time h (horizontal axis) and the elongation at break E (vertical axis) at each heating temperature w.

FIG. 5 is a group of graphs showing the relationship between the heating temperature (horizontal axis) and the heating time (vertical axis) for each value of the elongation at break. The horizontal axis shows the reciprocal of the absolute temperature T as the heating temperature, and the vertical axis shows the logarithm of the heating time h.

FIG. 6 is a flowchart showing the operation of the deterioration diagnosis program executed in the deterioration diagnosis device of the present invention.

FIG. 7 is a group of graphs showing the relationship between the heating time and the elongation at break for each heating temperature w obtained for the sample in the example of the present invention.

FIG. 8 is a group of graphs showing the relationship between the heating temperature and the heating time for each value of the elongation at break obtained for the sample in the example of the present invention. Detailed description of the invention The deterioration diagnosis method of the present invention has at least the following steps.

(1) Prepare a sample of the same material as the coating layer of the article to be diagnosed (for example, a cable in a laid state), and evaluate the deterioration diagnosis characteristics (hereinafter “diagnosis characteristics”) of the sample and the corresponding ultrasonic wave propagation. The characteristics (hereinafter referred to as “propagation characteristics”) are measured, and a data group for deterioration diagnosis is created in which the values of the diagnosis characteristics correspond to the values of the propagation characteristics.

(2) The ultrasonic wave is transmitted to the surface of the coating layer and near the surface of the article to be diagnosed, and the propagation characteristics of the coating layer are measured.

(3) Using the data group (2) above, determine the diagnostic characteristics corresponding to the propagation characteristics of the article obtained in the measurement (2) above, and use this as the diagnostic characteristic of the article to perform the deterioration diagnosis of the article.

The articles subject to deterioration diagnosis need only have at least a coating layer made of an organic polymer material, and include not only cables but also pipes, hoses, sheet materials, wall materials, and surface materials such as floor materials. Can be The cable includes all electric wires having a coating layer made of an organic polymer material, and includes, for example, an insulated electric wire and a power cable, and may be used for any purpose such as communication, power, and equipment. For these cables, the deterioration of the coating layer is a serious problem, and the cables in the laid state cannot be subjected to destructive inspection. Will be noticeable.

The diagnostic characteristic may be a characteristic that can indicate the degree of deterioration of the organic polymer material used for the coating layer (hereinafter, also referred to as “the material of the coating layer”) and has a correlation with the propagation characteristic. For example, surface rebound hardness, surface penetration hardness, tensile strength, elongation at break, elastic modulus, Young's modulus, modulus, dielectric constant, dielectric loss tangent, volume resistivity, AC breakdown voltage strength, impulse breakdown voltage strength, articles The mechanical characteristics and electrical characteristics such as torsional torque and bending stiffness of a long object such as a cable. In particular, the elongation at break shows the degree of deterioration of the coating layer of the cable remarkably, and has a strong correlation with the propagation characteristics, so that it is preferably used as a diagnostic characteristic.

In the case of cables, in general, when the elongation at break of the cable coating layer approaches 50%, cracks tend to occur due to vibration or impact, and as a result, water intrusion from the outside may occur. May cause dielectric breakdown. Therefore, it is considered that the replacement of the cable should be performed with the elongation at break of about 50% as a guide. However, the criteria for the deterioration index may be determined by the user as appropriate.

The propagation characteristic may be an amount that indicates a propagation state when an ultrasonic wave is propagated in the material of the coating layer and has a correlation with the deterioration of the material. For example, the propagation time when the propagation distance is constant, the propagation speed calculated from the propagation distance and the propagation time, the ultrasonic reception sensitivity, the change in the ultrasonic waveform frequency, the change in the ultrasonic waveform shape, the attenuation of the ultrasonic wave Characteristics and the like. In particular, propagation time and propagation speed are useful. The method of measuring the propagation characteristics will be described later together with the description of the device.

The following are examples of the organic polymer material used for the coating layer.

The thermoplastic resins include polyolefins such as polyethylene, polypropylene, polybutene, poly (4-methylpentene-1), ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polyamides such as nylon, and others. Examples of rubber include vinyl chloride, polyvinylidene chloride, and thermoplastic polyester. Examples of rubber include natural rubber, isoprene rubber, butyl rubber, ethylene-propylene copolymer rubber, ethylene-propylene-gen terpolymer rubber, and styrene-butadiene copolymer. Rubber, acrylonitrile-butadiene copolymer rubber, ethylene-vinyl acetate copolymer rubber, ethylene-ethyl acrylate copolymer rubber, chlorosulfonated polyethylene rubber, epichlorohydrin rubber, silicone rubber, fluorine rubber, etc. No.

Thermoplastic elastomers include styrene-based thermoplastic elastomers such as ABA-type triblocks and (AB) „X-type radial blocks, and polyolefin-based thermoplastics such as blend-type TP0, partially cross-linked blended TPO, and fully-crosslinked blended TPO. Elastomer, nitrile rubber blend ゃ Polyvinyl chloride thermoplastic elastomer such as partially cross-linked nitrile rubber blend, polyurethane thermoplastic elastomer such as polyester type or polyether type, polyester ポリ polyether type ゃ Examples include polyester-based thermoplastic elastomers such as polyester and polyester.

The data group may be continuous or discrete. That is, even in a data group in which a continuously changing diagnostic characteristic and a correspondingly continuously changing propagation characteristic are recorded, the value of the changing diagnostic characteristic at each specific interval and each value are It may be a data group in which the values of the corresponding propagation characteristics are recorded. It is preferable that the data group be prepared in advance for various materials prior to the diagnosis of the article, and if it is held so that it can always be referred to, the diagnosis results can be quickly obtained from the measurement of the actual product using ultrasonic waves. can get. When creating a data group, it is necessary not only to make the “diagnosis characteristics” and “propagation characteristics” correspond in a two-way fashion, but also to add the “elapsed time” element to these, The data group may be a three-way correspondence of the “diagnosis characteristic” and the “propagation characteristic”. Further, other elements may be added to form a group that can handle multiple factors. In addition, as described later, a special data group corresponding to “specific deterioration factor value”, “elapsed time”, and “diagnosis characteristic” may be formed in order to estimate the remaining life.

By adding “elapsed time” as an element to the data group, it is not only possible to judge the magnitude of the mechanical and electrical characteristics of the material, but also to determine the diagnostic characteristics based on the temporal changes in the propagation characteristics. The change can be known, and the degree of deterioration of the article can be diagnosed from the change over time. In addition, comprehensive diagnosis including evaluations related to the passage of time, such as an evaluation of the degree of deterioration of the article over use time and an estimation of the remaining life (remaining life) can be performed. In particular, the estimation of the remaining life is not for deterioration until the measurement point, but for the diagnosis of the progress of deterioration after the measurement point, and is a useful deterioration diagnosis for equipment such as cables.

To create a data group, the sample is deteriorated by changing the conditions such as irradiation and heating, and the diagnostic characteristics are changed while the propagation characteristics are measured at the same time. What is necessary is just to record in the state corresponding to 1. When the sample is deteriorated, if the article is a cable, it should be deteriorated according to the environment in which it is laid. For example, in the case of cables laid at facilities related to nuclear power plants, radiation dose 10 The degradation may be performed at k G y / h or less and at a temperature of 250 ° C. or less. In order to deteriorate the sample, the rate of progress of deterioration may be accelerated under more severe conditions as in the accelerated test. However, when an accelerated test is performed by adding an element of “time lapse” to the data group It is preferable that the accelerated elapsed time and the elapsed time under the actual use environment be corresponded so as to be able to be converted.

When the degradation diagnosis is performed on a cable, if the coating layer is made of polyvinyl chloride, a phthalic acid-based trimellitate-based plasticizer and a filler are usually blended. When the material is a rubber-based material or a polyethylene-based material, a filler and carbon are usually blended.

In the present invention, it is taken into consideration that the correlation between the propagation characteristics and the diagnostic characteristics is different if the types and amounts of the plasticizers and fillers added to the material of the coating layer are different. Therefore, for each type of coating layer material, one or more types of plasticizers, plasticizers, fillers, and carbons are selected and changed to obtain material specifications. It is preferable to create a data group by measuring the diagnostic characteristics and the corresponding propagation characteristics for each sample having different specifications.

For the articles to be diagnosed, measure the propagation characteristics and determine the above material specifications. The combination of these propagation characteristics and material specifications is converted into diagnostic characteristics using the above data group, and deterioration diagnosis is performed according to the material specifications.

For example, for cables, diagnosis is performed in the following steps (1) to (3).

(1) The type of plasticizer, the amount of plasticizer, the amount of filler, and the amount of carbon compounded according to each organic polymer material used for the material of the cable coating layer are changed as a whole. A data group is created by obtaining the relationship between the propagation characteristics and the diagnostic characteristics (physical characteristics and / or electrical characteristics) of each organic polymer material at the time.

(2) Based on the information obtained from the coating layer of the cable to be diagnosed, select the relationship between at least one of the propagation characteristics and the diagnostic characteristics from the data group of (1) above.

(3) The propagation characteristics of the coating layer of the cable to be diagnosed are obtained, and the diagnostic characteristics of the cable coating material are obtained from this and the relationship selected in (2), and the deterioration state of the coating layer of the cable is obtained. Diagnose.

According to experiments performed by the present inventors, when the material of the coating layer is polyvinyl chloride, the amount of the phthalate-based plasticizer does not affect the correlation between the propagation characteristics and the diagnostic characteristics. The amount of the acid ester-based plasticizer has an effect. In addition, the amount of filler affects the amount of the mixture, and the type does not. If the material is chloroprene rubber (without filler), the carbon loading will affect the correlation. Also, when the material is polyethylene, the amount of the filler affects the correlation.

Information on the cable covering material to be diagnosed, such as the type of polymer material, the type of plasticizer compounded in the polymer material, the amount of plasticizer, the amount of filler, and the amount of carbon, It can be obtained as follows.

The type of polymer material can be determined non-destructively from the hardness of the cable covering material, installation records and manufacturing records. Usually, it is sufficient to determine whether the material is polyvinyl chloride, rubber material, or polyethylene material. If printed on the cable, you can still find it. For example, if “IV” is printed on the surface of the cable, it is a vinyl insulated cable, and if “cV” is printed, it is a polyethylene insulated vinyl sheath. If it cannot be obtained by the above, it can be obtained by taking a small amount of cable coating material and performing thermogravimetric analysis or measurement of infrared absorption spectrum.

The type and blending amount of the plasticizer can also be determined from the installation record and the production record. However, if these are not required from the above, for example, solvents (acetone, methanol,

Using a cotton wool containing THF, etc., a plasticizer is collected by rubbing the surface of the cable covering material in the laid state, and the components in the cotton wool are analyzed by infrared absorption spectrum, GPC (gel filtration chromatography), HPLC ( It can be determined nondestructively by analyzing with high performance liquid chromatography).

The blending amount of the filler can also be determined from the installation record and the production record. However, if these cannot be determined, a small sample (a few mg) can be collected from the laid cable and analyzed by TGA (thermogravimetric analysis). You can ask. The amount of carbon can be determined in the same manner.

As described above, the type of the plasticizer may be determined as needed when the polymer material is polyvinyl chloride. Generally, a phthalate plasticizer is often used as a plasticizer, and a trimellitate plasticizer is used when heat resistance is required. The amount of the plasticizer may be determined as needed when the plasticizer is trimellitic acid. The compounding amount of carbon may be determined as needed when the polymer material is a rubber material / polyethylene material.

In the present invention, the propagation characteristics are measured by propagating ultrasonic waves to and near the surface of the coating layer of the article. A method for measuring the propagation characteristics will be described below while explaining a part of the deterioration diagnosis device of the present invention.

The deterioration diagnosis device of the present invention has at least the measuring device (A) shown in FIG. The measuring device (A) includes an ultrasonic transmitting means (hereinafter referred to as “transmitting means”) 1, an ultrasonic receiving means (hereinafter referred to as “receiving means”) 2, and delay chips 11, 21 provided for each of them. And a propagation time measuring means 3.

The propagation time measuring means 3 is a device for measuring a time (propagation time) from when the ultrasonic wave is transmitted from the transmitting means to when it is received by the receiving means.

As will be described in detail later, the delay chips 11 and 21 intervene when the transmitting means 1 and the receiving means 2 are installed on the surface of the object to be measured, and refract the propagation direction of the ultrasonic wave. It is configured so that it can be sent along the surface of the object to be measured, and that it can receive ultrasonic waves that have propagated along the surface. The transmission means 1 includes at least an ultrasonic vibrator (not shown). Ultrasonic transducers are conversion elements that convert electrical signals into ultrasonic waves. The transmitting means 1 is capable of transmitting the ultrasonic waves emitted by the vibrator into the coating layer of the object to be measured. The transmitting means 1 is provided via a delay chip 11 on a surface of a coating layer C1 of a cable C which is an example of an object to be measured. The receiving means 2 includes at least an ultrasonic detecting element (not shown). An ultrasonic detection element is a conversion element that converts an ultrasonic wave into an electric signal. The receiving means 2 is capable of converting the ultrasonic wave emitted from the transmitting means and propagating through the coating layer into an electric signal by the detection element and receiving the electric signal. The receiving means 2 is provided on the surface of the coating layer C1 of the cable C via the delay chip 21 at a position away from the transmitting means 1 by a distance L1.

With the configuration of the measuring device (A), the ultrasonic waves transmitted from the transmitting means 1 enter the coating layer of the object to be measured via the delay chip 11. Since the delay chip 11 is made of a material selected in terms of the ultrasonic wave propagation velocity with respect to the material of the coating layer and the inclination angle is selected, as described by Snell's law, the ultrasonic wave is The propagation direction is changed at the interface with the layer, the light propagates linearly on the surface of the coating layer and near the surface to the position of the receiving means, and is received by the receiving means 2 via the delay chip 21. The propagation time t at that time is measured by the propagation time measuring means 3.

Propagation of ultrasonic waves only on and near the surface of the coating layer (hereinafter referred to as “along the surface of the coating layer”), and direct communication between the transmitting and receiving means As a result, the propagation characteristics can be determined only by the amount that can be clearly measured from the outside, and difficult-to-measure amounts such as the thickness of the coating layer are not required. The deterioration diagnosis method of the present invention can be preferably performed by the deterioration diagnosis device of the present invention having the above-mentioned measuring device (A).

The delay chip will be described with the transmission side as a representative. As shown in Fig. 2, the delay chip has a wedge-shaped inclined part to which an ultrasonic transducer (detection element in the receiving means) is attached, so that the vibration surface of the ultrasonic transducer and the surface of the measurement object are separated. Intervening between them so as to form an angle 0. This angle 0 is the incident angle 0 (the angle formed by the surface normal X). The basic structure of the delay chip may refer to the prior art. In FIG. 2, the transmitting means 1 is arranged on the surface of the coating layer C1 of the measuring object C via the delay chip 11. Figure 2 shows that the propagation speed of the ultrasonic wave in the delay chip VI is less than the propagation speed of the ultrasonic wave in the material of the coating layer. FIG. 4 is a diagram in which the material of the delay chip is selected.

By the delay chip 11, the ultrasonic wave enters the coating layer C1 at an incident angle, is refracted at the interface so as to have a refraction angle of ø, and propagates in the coating layer C1. This is as explained by Snell's law (the law of refraction).

In the present invention, the value of VI with respect to V 2 and V i are selected so that the ultrasonic wave propagates along the surface of the coating layer after refraction. In practice, it is possible to obtain a component that propagates along the surface of the coating layer even if it deviates slightly from Snell's law, but it is more efficient to follow Snell's law.

In the present invention, ultrasonic waves are propagated on and near the surface of the coating layer. The surface of the coating layer where the ultrasonic wave propagates and the vicinity of the surface are mainly the area at a depth of about 3 mm from the surface of the coating layer. Therefore, there is no problem if the coating layer is sufficiently thick. However, for example, when the thickness is only 1.5 mm, a part of the ultrasonic wave may be below the coating layer (in a cable, for example, adjacent to the conductor layer or the like). The light is reflected at the interface with the next layer, or is repeatedly reflected between the interface and the surface of the covering layer, and propagates, so that accurate propagation characteristics may not be measured in some cases. Therefore, in order to measure more accurately, for example, the ultrasonic wave is propagated at the surface of the coating layer and at a depth of about 1 mm from the surface. It is preferred that the light be propagated in a localized manner. The material of the delay chip is selected with respect to the material of the coating layer such that VI is not more than 1 time, more preferably VI is not more than V2, particularly preferably VI is not more than 0.97 times V2. I do. It is more efficient to select such that V 1 <V 2 because the angle of incidence and the angle of refraction are ø and Snell's law is well followed. 0 at that time is preferably about 20 ° to 85 °.

Propagation velocity V1 in an undegraded organic polymer material is about 180 m / s for polyethylene, about 180 OmZs for polyvinyl chloride, and ethylene-propylene copolymer rubber (EPM). About 150 m / s for polytetrafluoroethylene, about 1300 m / s for silicone rubber and about 100 Om / s for silicone rubber. Therefore, the measurement target was polyethylene, polyvinyl chloride, ethylene-propylene copolymer rubber (E When PM is used, polytetrafluoroethylene or silicone rubber is preferable as the material of the die chip, since V 1 <V 2.

The frequency of the ultrasonic wave used in the present invention is not limited. Note that organic polymer materials, such as polyethylene, polyvinyl chloride, and ethylene-propylene copolymer rubber (EPM), which are frequently used for the coating layer of cables, generally have a relatively low attenuation because ultrasonic waves have a large attenuation. A frequency of about 5 to about 5 MHz, particularly about 0.5 to 2 MHz is preferable.

The overall configuration of the deterioration diagnosis device of the present invention including other elements will be described after the description of the deterioration diagnosis method.

The present invention provides two preferable methods (I) and (II) for measuring propagation characteristics. Any of these methods can be preferably implemented by using the deterioration diagnosis apparatus of the present invention. These methods will now be described.

First, the method (I) employs the propagation speed as the propagation characteristic, and measures the propagation speed. As shown in FIG. 1, a transmitting means 1 and a receiving means 2 are placed on the surface of a measurement object via delay chips 11 and 21, respectively. As is clear from the description of the device, the ultrasonic wave transmitted from the transmitting means 1 propagates linearly to the installation position of the receiving means 2 along the surface of the object to be measured. In this state, the installation interval between the transmitting means 1 and the receiving means 2 is changed to L1 and L2, and the total propagation times t1 and t2 at each time are measured.

At this time, in the delay chip 11 (propagation velocity V 11, propagation distance L 11, propagation time t 11), and in delay chip 21 (propagation velocity V 21, propagation distance L 21, propagation time t 21), and within the coating layer C 1 (propagation speed V, installation interval (= propagation distance) Lx 1, propagation time tx, and propagation distance L 2, propagation time ty), the following equation ( 1) and (2) hold.

t l = t l l + t x + t 21

= (L 1 1 / V1 1) + (L 1 / V) + (L 21 / V 21) (1) t 2 = tll + t y + t 21 = (L 1 1 / V 1 1) + (L 2 / V) + (L 2 1 / V 2 1) · (2) From the above equation (1)-(2), the propagation velocity V = ( L 2 — L 1) no (t 2-t 1) is derived. As is clear from this equation, the propagation velocity V in the coating layer C1 is determined only by the installation interval and the total propagation time without being influenced by the propagation time required for the delay chip or the thickness of the coating layer.

It is preferable that the deterioration diagnosis apparatus according to the present invention be provided with an installation interval measuring means for measuring an interval between the transmitting means 1 and the receiving means 2. Further, the measuring means may be provided not only with a simple measuring function but also with a mechanism capable of setting an installation interval between the transmitting means and the receiving means to a desired value. For example, it has a structure in which the distance between the transmitting means and the receiving means can be directly read and finely adjusted using a micro head or the like.

Ultrasonic waves propagating in a solid, particularly in an organic polymer material, are extremely easily attenuated, so that the value of L1 or L2 is preferably several hundred im to several tens mm.

Next, the method (II) employs the total propagation time from oscillation to detection when the propagation distance is constant as the propagation characteristic. The method of measuring the propagation time itself is the same as the measurement of the total propagation time t1 or t2 in the above method (I), and is preferably performed using the deterioration diagnosis apparatus of the present invention.

In the method (II), the propagation time is always measured at the same propagation distance in both the measurement of the data group and the measurement of the article. Preferably, measurement devices having the same specifications are used. If the delay chips always have the same specifications and the installation intervals are always constant, the amount of change is substantially only the propagation speed due to the deterioration of the coating layer, and the propagation time can directly correspond to the diagnostic characteristics. By always using the propagation time for the evaluation, it is not necessary to perform calculations for eliminating the time related to the two delay chips shown in the method (I) above. In other words, it is possible to make the measured value correspond to the diagnostic characteristics in the data group as it is, by performing only one measurement of the propagation time for the cable covering layer of the laid cable, making degradation diagnosis easier and more accurate. Becomes Furthermore, by combining the above-mentioned “elapsed time” elements, a simple measurement of the propagation time for an article enables easy and accurate comprehensive diagnosis including time-dependent changes. Will be able to

The present invention focuses on the fact that when the article is a long object, the degree of deterioration differs along the longitudinal direction. This will be described for the cable. In the laid cable, the environment greatly differs in the longitudinal direction of the cable, and the degree of deterioration of the coating layer also varies greatly in the longitudinal direction. In the conventional deterioration diagnosis method, since the selected site is diagnosed without considering this point, there may be a large difference between the diagnosis result and the actual degree of deterioration.

In the present invention, how the deterioration factors that deteriorate the coating layer of the cable are distributed along the longitudinal direction is measured, and based on the result, deterioration diagnosis is performed for a portion where the deterioration factors greatly affect. This makes it possible to make a diagnosis that is in line with the actual state of deterioration. In addition, knowing the parts that are greatly affected by the deterioration factors and improving the environment of those parts can delay the progress of cable deterioration and extend the service life.

The method for measuring how the deterioration factors are distributed in the longitudinal direction of the laid cable is not limited. For example, using one measuring means capable of measuring the degree of the deterioration factor, the measurement may be performed sequentially along the longitudinal direction of the laid cable, and the measuring means may be provided at least in one section of the laid cable. (Equipment) may be installed along the longitudinal direction of the cable, and multiple points may be measured simultaneously.

Deterioration factors include temperature, humidity, water, PH of substances surrounding the coating layer, oil, hydrogen sulfide, oxygen, ozone, other reactive gases, sunlight, radiation Examples of the material that mechanically degrades the material of the coating layer include various forces acting on the cable from inside and outside, and vibrations and distortions generated at various portions of the cable. An important degradation factor is selected from these factors, and the distribution of the factor is measured by a measuring device capable of detecting the factor.

The measurement interval along the cable or the installation interval of the measurement device may be determined according to the cable installation situation and environment. For example, outdoor radiation doses, concentrations of reactive gases such as hydrogen sulfide, oxygen, and ozone in the atmosphere, humidity, and solar radiation are relatively wide ranges. Since it is substantially constant over the circumference, an interval of about 5 to 5 Om is sufficient. On the other hand, the radiation dose received by the coated cable laid in the nuclear power plant, the immersion of the coated cable laid on the road in the production plant in water, and the adhesion of oil occur in a relatively narrow range. An interval of about 1 Om, and in some cases, about 0.5 to 2 m is preferable. A case where an apparatus for measuring a deterioration factor is installed along a cable will be described. For example, when measuring temperature, it is preferable to use an adhesive tape, for example, so that the temperature-sensitive part of the measuring device contacts the surface of the coated cable. Also, when measuring the humidity in the atmosphere, the substances around the cable, the concentration of hydrogen sulfide, the concentration of oxygen, the amount of solar radiation, or the amount of radiation, the sensing part of the measuring device must be in contact with or near the insulated cable, For example, it may be installed at a position about 1 to 50 cm away from the surface of the coated cable. In order to detect whether or not oil has adhered to the surface of the coating layer of the cable, for example, a sensor having a rubber in the sensing unit that swells with oil and changes the electric resistance value is exemplified. To detect the force acting on the cable and the strain generated in the cable, a strain gauge may be installed on the surface of the coating layer.

Deterioration factors may be measured continuously or at regular time intervals. The time interval depends on the deterioration factors and the goods (especially cables), and for example, once an hour, once a day, or even once a year may be sufficient. As described above, one of the degradation diagnoses of the present invention is estimation of the remaining life. That is, it is a diagnosis that indicates the degree of deterioration as the remaining time until the use limit. The present invention provides a preferred method of estimating the remaining life by adding "time lapse" to the data group as an element of the data. This will be described below using a cable as an example of an article.

In the present invention, the remaining life is estimated according to the following steps.

(1) By the deterioration diagnosis method according to the present invention, the ultrasonic propagation characteristics of the coating layer of the cable laid are measured, and a diagnostic characteristic value E1 corresponding thereto is obtained from the deterioration diagnosis data group. (2) Create a data group for remaining life estimation for samples of the same material as the coating layer. The data group for remaining life estimation is assumed to correspond to the diagnostic characteristic value E, the heating temperature, and the heating time h. The correspondence of this (diagnosis characteristic value E, heating temperature w, heating time h) will be described later in detail. The value E of the diagnostic characteristic includes the value Ez determined as the limit of use.

(3) Estimate the remaining life as follows from E1 of the actual measurement results and the data group for remaining life estimation.

① The use period of the laid cable is regarded as the heating time h1.

(2) From the data group for remaining life estimation, obtain the heating temperature w1 corresponding to the heating time h1 when the value of the diagnostic characteristic is E1.

(3) From the data group for remaining life estimation, obtain the heating time hz corresponding to the heating temperature w1 when the value of the diagnostic characteristic is Ez.

差 Let the difference between h z and h 1 (h z — h 1) be the remaining life. The above steps (1) to (3) will be described in more detail using actual data. The article is a cable and the diagnostic properties are the elongation at break.

Step (1) may be performed by using the deterioration diagnosis method according to the present invention, and is as described above.

An example of a specific procedure for creating a data group for remaining life estimation in step (2) will be described. As shown in FIG. 5, the shape of the data group for remaining life estimation obtained in this step is such that the value E of the diagnostic characteristic, the heating temperature w, and the heating time h correspond to each other. That is, the correlation between w and h at each value of E when E is varied as a parameter (hereinafter referred to as wh correlation).

The material of the sample used to experimentally establish the w-h correlation may be a material having the same composition as the material of the coating layer of the cable whose remaining life is to be estimated, or a similar material. Similar materials can be used if they are based on the original organic polymer materials and their degradation diagnostic characteristics E match within 20% of soil. Is available. A sample in the form of a sheet (for example, about 1 to 5 mm thick) is processed by pressing. The sample may be an undegraded remaining life estimation object itself in place of the sheet.

As a preferable data preparation procedure, as shown below, the sample was heated at various heating temperatures w, and for each heating temperature w, the change in the elongation at break E with respect to the heating time h was measured, and shown in FIG. Thus, the relationship curve between h and E for each value of w is obtained, and based on this, the relationship curve between h and w for each value of E is converted as shown in FIG. It is preferable to use a data group for estimation. The value of E includes the value E z determined as the service limit. E z may be set taking into account the type of material, management criteria for user use, and other circumstances.

The heating temperature w is preferably in a wide temperature range and in small increments, but in general, heating at a low temperature of 90 ° C or less slows the progress of deterioration. It is preferable to set the interval at least at 50 ° C, particularly at 20 ° C within the range.

The heating time h is preferably at least one month, especially at least three months. Fig. 4 is a model graph of the results, which shows the relationship between the heating time h (horizontal axis) and the elongation at break E (vertical axis) at different heating temperatures w (wl to w4). Data group).

Next, the relationship between h and E for each value of w is converted to the relationship between h and w for each value of E. Fig. 5 shows an example of this. The heating temperature (horizontal axis) and the elongation at break E (100%, 150%, 200%, 250%, 300%) are shown for each different elongation at break. It is a graph group (data group) showing a relationship with the heating time (vertical axis), and shows a so-called Arrhenius curve. For the purpose of explanation, the use limit E z of the elongation at break E is set to 100%, and the graph is shown by a thick line.

When obtaining the Arrhenius curve shown in Fig. 5 from the data read from Fig. 4, it is recommended that the least square method be used to find a linear equation (straight line) that minimizes the correlation coefficient, or a quadratic or higher polynomial However, in many cases, it can actually be approximated by a linear equation (straight line) In step (3), the use period (laying period) of the laid cable is regarded as the cable heating time h1. Then, assuming that the value of the elongation at break of the coating layer of the actual cable obtained in step (1) was 250%, heating was performed at point a on the graph of E = 250% in FIG. The heating temperature w1 corresponding to the time h1 is obtained. Then, the heating time hz of the limit corresponding to the heating temperature wl at the point b is obtained on the graph of the usage limit E = 1100% (= Ez) in FIG. Finally, the difference (hz-h1) between the limit heating time hz and the heating time (= laying period) h1 is determined, and this is taken as the remaining life. Next, the overall configuration of the deterioration diagnosis apparatus according to the present invention will be described.

FIG. 3 shows an example of this, and in addition to the configuration shown in FIG. 1, transmission control means 12, reception control means 22, propagation time measurement means 3, calculation means 4, distance input means 5, determination means 6 The arrangement of the display means 7 is clearly shown.

The transmission control means 12 has a function of inputting the transmission time of the ultrasonic wave from the transmission means 1 and the like to the propagation time measurement means 3 described later as an electric signal. The reception control means 22 has a function of inputting the reception time of the ultrasonic wave from the reception means 2 to the propagation time measurement means 3 as an electric signal. The propagation time measuring means 3 calculates the time required from transmission to reception based on the signal. The method of measuring the propagation time is not limited to the above. For example, a counter or a clock is arranged inside the propagation time measuring means 3, and a signal notifying the start of transmission from the transmission control means 12 and a signal notifying that the signal has been received from the reception control means 22 are used as described above. Start and stop clocks, etc., and measure the propagation time.

In the method (I), the installation intervals L 1 and L 2 between the transmitting means 1 and the receiving means 2 are stored in the distance input means 5. Further, the propagation times t 1 and t 2 are measured by the propagation time measuring means 3. The calculating means 4 calculates the above-described propagation velocity V from the data L1, L2, t1 and t2.

The judging means 6 holds various data for diagnosis of deterioration of the material of the coating layer, and converts the value of the propagation characteristic inputted from the arithmetic means 4 into the value of the diagnosis characteristic, The degree is determined, and the result is sent to the display means 7 to be displayed in various display methods, for example, a graph showing the relationship between the number of operating days and the degree of deterioration of the insulated wire.

The deterioration diagnosis device of the present invention may be configured by connecting individual independent devices. However, the measurement device of (A) (including a driving system such as an ultrasonic transducer, a detection element, and a driver thereof) may be used. Except for), all may be controlled centrally by computer. Depending on the configuration of the device, the propagation time measuring means 3 may be externally provided as an independent measuring device to exchange data with a computer.

The data group described above is stored in the storage device of the computer. The propagation characteristic may be calculated at the stage of the measurement device (A) or may be calculated by a central processing unit. In any case, the central processing unit performs a process of extracting the value of the diagnostic characteristic corresponding to the obtained propagation characteristic from the data group for deterioration diagnosis stored in the storage device.

When the main body of the central processing unit of the deterioration diagnosis device of the present invention is a computer, it is preferable to perform the deterioration diagnosis using the computer. Examples of the diagnostic program to be executed include the above (B). The following is a specific example of the deterioration diagnosis program. The propagation speed is used as the propagation characteristic, and the elongation at break is used as the diagnostic characteristic. In the example of this program, the deterioration diagnosis is performed in consideration of the type and the amount of the plasticizer and filler added to the material of the coating layer described above.

As shown in the flowchart of FIG. 6, first, in step S1, the program requests input of the type of the organic polymer material that is the material of the coating layer. When the information is input, the process proceeds to step S2, where it is determined whether the material type is polyvinyl chloride (PVC), a rubber-based material, or a polyethylene-based material.

If the material is PVC in step S2, the program moves to step S3 and requests input of the type of plasticizer. When this is input, the process moves to step S4, where it is determined whether the plasticizer is a phthalate ester or a trimellitate ester.

If the plasticizer is a phthalate ester in step S4, the program Proceed to step S5 to request input of the blending amount of the filler. When it is input, the process moves to step S9. On the other hand, if the plasticizer is trimellitic acid ester in step S, the program moves to step S6 and requests the input of the blending amount and the blending amount of the filler. When it is input, the process moves to step S9. If the plasticizer has not been blended, the program proceeds to step S5 and requests the input of the blending amount of the filler. In Steps S5 and S6, if there is no compounding, for example, the operator inputs “zero”, “0”, and the like.

If the material is a rubber-based material in step S2, the program proceeds to step S7, where the amounts of the filler and the carbon are obtained, and then the program proceeds to step S9. For those that are not blended, the operator inputs "zero" as above.

If the material is a polyethylene-based material in step S2, the program proceeds to step S8, and after obtaining the input of the amount of the filler and the amount of the solvent, the program proceeds to step S9. For those that are not blended, the operator inputs “zero” as above.

When information on the material of the coating layer is input in this way, the program selects data having the same conditions as the information input from the data group in step S9 as data D. The data group may be created by the above-described procedure and stored in various internal and external storage devices and recording media.

In step S10, the measured propagation velocity V of the material of the covering layer is calculated from the numerical value input from the external measuring device. Subsequently, in step S11, the elongation at break H corresponding to the propagation velocity V is selected from the data D. In step S12, the deterioration state of the cable coating material is diagnosed using the elongation at break H as a deterioration index.

In FIG. 6, the type of material, the type and blending amount of plasticizer, the blending amount of filler, and the blending amount of carbon are input. However, the present invention is not limited to this example. It may be at least one ^ ^. For example, only the type of material may be used. In addition, The estimation may be performed by a program. Example

Example 1

In this example, the propagation characteristics of the cable coating layer were measured by the method (I) using the deterioration diagnosis apparatus shown in FIG.

The object to be measured is a power cable immediately after manufacture, which has a sheath (coating layer) made of soft polyvinyl chloride with an outer diameter of 21 mm and a nominal thickness of 2.5 mm. Both the transmitting means 1 and the receiving means 2 were installed on the surface of the cable coating layer via an oblique angle derailleur (inclined angle: 40 °) made of polytetrafluoroethylene.

The two types of installation intervals L 1 and L 2 are 1 mm and 10 mm, respectively, and the propagation times t 1 and t 2 at L l and L 2 are respectively determined using ultrasonic waves with a frequency of 1.0 MHz. Measurements were made to determine the transit time difference (t 2-t 1). The number of data in each of t l and t 2 is n = 10. As a result, the average value of (t 2-t 1) is 4.86〃s. From V = (L 2 -L 1) / (t 2 -t 1), the propagation velocity in the coating layer is 1 85 0 m / s was obtained.

When a portion of the coating layer was taken out of the cable and its propagation velocity was accurately measured, it was 1852 m // sec. From this, it was confirmed that the method (I) using the deterioration diagnosis device according to the present invention can measure propagation characteristics well and is useful.

After heating the above cable in an oven with air circulation at 130 ° C for 10 days to deteriorate it, measure t 1 and t 2 by the same method as above, The propagation velocity at was obtained. As a result, the average value of (t 2-t 1) was 3.95 μs, and the propagation velocity in the coating layer was 228 OmZ seconds. From this, it was confirmed that the propagation speed changes as the material of the coating layer deteriorates. Example 2

In the present embodiment, a data group in which the propagation characteristics correspond to the diagnostic characteristics was created, the propagation characteristics were measured for the actual product, and the diagnostic characteristics corresponding to the measured values were obtained from the data group. In addition, a method of obtaining a diagnostic characteristic from a data group by performing only one measurement of the propagation time, instead of measuring the propagation distance as in Example 1, while keeping the propagation distance constant, was performed.

The object to be measured is a power cable laid for 10 years and has a coating layer made of soft polyvinyl chloride with an outer diameter of 2 lmm and an actual thickness of 2.5 mm. The propagation time of the ultrasonic wave was measured in the same manner as in Example 1 except that the installation interval (the distance between the tip ends of both delay chips) was set to 2 mm using the deterioration diagnosis apparatus shown in Fig. 1. On the other hand, a sheet (thickness 3 mm なる) made of the same material as the coating layer was used as a sample, and the sample was heated and acceleratedly degraded to form various samples with different degrees of degradation. The correlation between the elongation rate and the propagation time was established separately, and the data was collected. The method of measuring the propagation time for the sample is the same as the measurement for the power cable described above. From this data group, a breaking elongation of about 220% corresponding to the propagation time measured with the above-described power cable was obtained.

A portion of the covering layer of the power cable was taken out, a dumbbell specimen was punched out, and the elongation at break was measured and found to be 228% on average. From this, it was found that the deterioration diagnosis method of the present invention agreed well with the results of the soil fracture test. Example 3

In the present embodiment, the remaining life is estimated as one of the deterioration diagnosis methods according to the present invention. The object is a signal cable that has been laid outdoors for 5 years, and has a 1.0 mm thick polyvinyl chloride insulation layer on a 1.0 mm diameter stranded copper conductor. This is a 600 V power cable with a 1.5-mm-thick polyvinyl chloride coating layer (sheath). The coating layer made of polyvinyl chloride is 100 parts by weight of polyvinyl chloride, 50 parts by weight of diisononyl phthalate as a plasticizer, and trisalt as a stabilizer. It contains 6 parts by weight of basic lead sulfate and 60 parts by weight of a brominated flame retardant as a filler. By the deterioration diagnosis method according to the present invention, the elongation at break of the coating layer of the cable was found to be an average of 272% (n = 20). The average sheath temperature during the five-year installation was about 40 ° C.

On the other hand, as a sample made of the same material as the above-mentioned coating layer, a sheet having a thickness of 5 mm was prepared, and the sheet was heated at a temperature of 100 to 120 ° C. in an oven in which air was circulated. At each temperature w, the change in elongation at break with respect to the heating time was measured, and the results shown in FIG. 7 were obtained.

An Arrhenius plot was performed based on the data obtained from Fig. 7, and a w-h correlation using the elongation at break shown in Fig. 8 as a parameter was obtained as a data group. Note that Fig. 8 shows only the low temperature range necessary for estimating the remaining life, and the vertical axis corresponds to the heating time in Fig. 7, but "years" was used to estimate the remaining life. Curve E1 is an Arrhenius curve with an elongation at break of 272%, and curve E2 is an Arrhenius curve with an elongation at break of 230%. From the curve E1 in FIG. 8, it can be seen that the temperature for the installation period of 5 years and the elongation at break of 272% is about 50 ° C. On the other hand, if the breaking elongation rate of 230% (curve E 2) is determined as the service limit, the period required for the breaking elongation rate to drop to 230%, that is, the remaining life, is about 13 years from Fig. 8. It is estimated to be.

When the elongation at break of another cable laid in the same environment (average sheath temperature is about 40 ° C) for 20 years was examined, the average elongation was reduced to 228% (n = 20). I was. From this, it was found that the above estimation result of the remaining life is a value that is sufficiently useful industrially. Comparative Example 3-1

Assuming that the cable of Example 3 is continuously operated under the condition that the average sheath temperature is 40 ° C, the remaining life is estimated at 40 ° C as in the conventional method. It turned out that it was one year, and it was far from the above confirmation result. Example 4

In this example, the remaining life was estimated for power cables laid outdoors for 9 years. The material of the coating layer (sheath) is flame-retardant black-mouthed plain. The cable has a 2.5 mm thick natural rubber insulating layer on a 2.Omm diameter stranded copper conductor, and a 3300 V thick 8 mm thick coating layer on top of it. Power cable. The coating layer is made of black mouth prene, and per 100 weight parts of black mouth prene. It contains 20 parts by weight of olefin oil, 60 parts by weight of aluminum silicate as a filler, and 25 parts by weight of carbon black, and is formed by heat crosslinking.

According to the deterioration diagnosis method of the present invention, the average elongation at break of the coating layer of the power cable was 3788% (n = 20). The average sheath temperature during the nine-year installation was about 45 ° C.

On the other hand, as a sample made of the same material as the above-mentioned coating layer, a sheet having a thickness of 2 mm was prepared by press molding and crosslinking at 150 ° C. for 30 minutes, and the sheet was subjected to 120 to 100 ° C. in an oven in which air circulated. Heat at a temperature of 150 ° C, measure the change in elongation at break with respect to heating time at each heating temperature w, perform Arrhenius plotting as in Example 3, and use the elongation at break as a parameter A linear w-h correlation was obtained as a data group. From the data group thus obtained (wh correlation), a temperature of about 58 ° C was obtained corresponding to a laying period of 9 years and a breaking elongation of 378%.

The elongation at break was determined as the service limit of 300%, and the period until the service limit was reached from the w-h correlation at the elongation at break of 300% was estimated to be about 7.5 years. When the elongation at break of another cable laid in the same environment (average sheath temperature is about 45 ° C) for 19 years was examined, the average elongation was 298% (n = 20). I was. From this, it was found that the above estimation result of the remaining life is a value that is sufficiently useful industrially. Comparative Example 41 Assuming that the cable of Example 4 is continuously operated at an average sheath temperature of 45 ° C and the remaining life is estimated at 45 ° C as in the conventional method, the estimated remaining life is 39 years. This proved to be significantly different from the above confirmation results. Example 5

In the present example, when performing the deterioration diagnosis of the coating layer of the cable, the deterioration diagnosis was performed in consideration of the type and the amount of the plasticizer and the filler added to the material of the coating layer.

[Selection of coating layer material information and data D]

Information on the material of the coating layer of the cable in the laid state was obtained from the record as described above, and the type of the polymer material was polyvinyl chloride, the plasticizer was a phthalate plasticizer, and the filler was filled. Information that the blending amount of the agent was 60 parts by weight was obtained. Based on this information, data D was selected from a data group created in advance.

[Determination of deterioration of cable coating layer]

For the material of the coating layer of the cable that was diagnosed above, measure the time from when the ultrasonic wave was transmitted to when it was received using a commercially available ultrasonic probe, and measured the ultrasonic wave in the coating material. When the propagation velocity was calculated, it was 2 15 O m Z s. The elongation at break corresponding to this actually measured value was determined from the selected data D, and obtained 190%.

[Evaluation]

The elongation at break of the coating layer of the cable subject to the above diagnosis was determined by the conventional method without considering the type and blending amount of the plasticizer, filler, etc., and the elongation at break was 140%. Met.

On the other hand, the coating layer of the cable to be diagnosed was broken, the test piece was taken out, and the elongation at break was measured by a tensile test to find that it was 190%.

From the above, it was found that the degradation diagnosis method of the present invention, which considers the types and amounts of plasticizers and fillers, etc., is a useful method that is closer to the results of destructive inspection. Also, when the deterioration diagnosis method of this embodiment is created as a computer overnight program as shown in the flowchart of FIG. The diagnosis could be made more quickly. Industrial applicability

INDUSTRIAL APPLICABILITY The present invention is suitable for a diagnosis of the degree of deterioration of a coating layer of an article for which nondestructive diagnosis is required, for example, a power cable in operation. ADVANTAGE OF THE INVENTION According to the deterioration diagnosis method of this invention, the propagation characteristic of this coating layer can be measured nondestructively and more accurately, without necessity of data, such as the thickness of a coating layer. Therefore, the diagnostic characteristics obtained from the data group also become more accurate. In addition, the introduction of “elapsed time” into the data group makes it possible to perform comprehensive deterioration diagnosis including changes over time, and to estimate the remaining life more accurately than before.

The present application was filed in Japan, filed in Japan, filed in Japanese Patent Application No. 320863, 1997, Patent Application No. 144,852, and Japanese Patent Application No. 150491, 1998. No. 5, Patent Application No. 1 549, 1989, and Patent Application No. 1, 634, 1984, which are all based on the contents of this book. You.

Claims

The scope of the claims

1. A method for diagnosing deterioration of an article having at least a coating layer made of an organic polymer material,

For the coating layer sample, the deterioration diagnostic characteristics and the corresponding ultrasonic propagation characteristics were measured, and a data group for deterioration diagnosis was created in which the values of the deterioration diagnostic characteristics corresponded to the values of the ultrasonic propagation characteristics.

By transmitting ultrasonic waves to and near the surface of the coating layer of the article, the ultrasonic propagation characteristics of the coating layer are measured, and the corresponding deterioration diagnostic characteristics are obtained from the data group. Diagnostic method.

2. The deterioration diagnosis method according to claim 1, wherein the article is a cable.

3. The deterioration diagnosis method according to claim 1, wherein the deterioration diagnosis characteristic is an elongation at break.

4. The data group for deterioration diagnosis is a data group including values of deterioration diagnosis characteristics that change over time, and values of ultrasonic propagation characteristics that change corresponding to each of the values. The degradation diagnosis method described in paragraph 1.

5. When preparing a data group for deterioration diagnosis, the type of organic polymer material, the type of plasticizer compounded in the organic polymer material, the amount of plasticizer, the amount of filler, and the amount of carbon By changing the material specifications consisting of one or more elements selected from the compounding amount of the sample, the deterioration diagnosis characteristics and the corresponding ultrasonic wave propagation characteristics are measured for each sample having different material specifications, and the data for deterioration diagnosis is measured. Create a flock,

2. The method according to claim 1, wherein the ultrasonic wave propagation characteristics of the coating layer of the article are measured, and a deterioration diagnostic characteristic corresponding to the ultrasonic wave propagation characteristics is obtained from a data group having the same material specifications as the coating layer. Diagnostic method.

6. The ultrasonic wave propagation characteristic is an ultrasonic wave propagation velocity, and the method of measuring the propagation velocity is as follows:

Ultrasonic transmitting means and ultrasonic receiving means are respectively installed on the surface of the object to be measured via delay chips, and the ultrasonic wave transmitted from the transmitting means passes through the measuring object while receiving the ultrasonic waves. With a configuration in which the light can propagate linearly to the installation position of the step and be received by the receiving means,

The propagation time tl, t2 of each ultrasonic wave is measured when the installation interval between the transmitting means and the receiving means is L1, L2, and (L2-L1) (t2-t1) 2. The method for diagnosing deterioration according to claim 1, wherein the method is a measuring method in which the value of is a propagation speed of ultrasonic waves.

7. The above-mentioned ultrasonic propagation characteristic is the propagation time of the ultrasonic wave when propagating over a specific distance, and the ultrasonic transmitting means and the ultrasonic receiving means are each a delay chip with the coating layer of the sample / article as the inspection object. The ultrasonic wave transmitted from the transmitting means is linearly propagated in the inspected object to the installation position of the receiving means, and the ultrasonic wave transmitted from the transmitting means is transmitted to the receiving means via the 2. The deterioration diagnosis method according to claim 1, wherein a time until reception through a delay chip is measured to obtain a propagation time.

8. The above article is a cable in a laid state, and it is measured how the deterioration factors which deteriorate the coating layer of the cable are distributed along the longitudinal direction of the cable, and the degree of the deterioration factors is measured. The deterioration diagnosis method according to claim 1, wherein the deterioration diagnosis is performed for a large portion.

9. In at least one section of the laid cable, measuring means capable of measuring the degree of the deterioration factor is installed along the longitudinal direction of the cable, and the distribution of the degree of the deterioration factor is measured. The deterioration diagnosis method described in paragraph 8.

10. The value of the above-mentioned deterioration diagnostic characteristic obtained for the coating layer of the article is E 1, and the value of the deterioration diagnostic characteristic is used for the sample of the same material as the coating layer.

The heating temperature t and the corresponding heating time h for each value of the deterioration diagnostic characteristics when Ez is changed are measured and used as a data group for remaining life estimation,

Using the data group for estimating the remaining life, the service period of the article is regarded as the heating time h1, and the heating temperature t1 corresponding to the heating time h1 at the value E1 of the deterioration diagnosis characteristic is obtained, and the deterioration is determined. The deterioration diagnosis method according to claim 1, wherein a heating time hz corresponding to the heating temperature t1 at the use limit value Ez of the diagnostic characteristic is obtained, and a value of hz-h1 is set as a remaining life. .

1 1. Diagnose deterioration of an article having at least a coating layer made of an organic polymer material. A degradation diagnostic device comprising at least the following measuring device (A).

(A) An apparatus for measuring ultrasonic propagation characteristics using a coating layer of an article or a sample of a coating layer as an object to be measured, the ultrasonic transmitting means, the ultrasonic receiving means, and these being disposed on the surface of the object to be measured. A delay chip of the following (A 1) to be interposed at each time of installation and a propagation time measuring means for measuring a time from when the ultrasonic wave is transmitted from the transmitting means to when the ultrasonic wave is received by the receiving means. Measuring device to have.

(A1) When the ultrasonic wave enters the measuring object from the delay chip, the inclination angle and the material are adjusted so that the propagation direction of the ultrasonic wave changes and the ultrasonic wave propagates on and near the surface of the measuring object. Delay chip that is selected.

12 2. The delay chip of (A 1) above has the following relationship with the organic polymer material: [propagation speed of ultrasonic wave in the delay chip] <[propagation speed of ultrasonic wave in the organic polymer material] 12. The degradation diagnosis device according to claim 11, wherein the degradation diagnosis device is made of a material selected to be the following.

13. The deterioration diagnostic device according to claim 11, wherein the article is a cable.

14. The deterioration diagnosis according to claim 11, wherein the deterioration diagnosis characteristic is an elongation at break.

15. The deterioration diagnostic apparatus according to claim 11, further comprising a measuring means for measuring an installation interval between the ultrasonic transmitting means and the ultrasonic receiving means on the coating layer.

1 6. It further has a central processing unit and a storage device,

The storage device stores a deterioration diagnosis data group including the deterioration diagnosis characteristic value of the material of the article coating layer and the corresponding ultrasonic propagation characteristic value,

The central processing unit uses the value of the ultrasonic propagation characteristic of the coating layer of the article obtained by the measuring device of (A) above and stores the value of the deterioration diagnosis characteristic corresponding to this value in the storage device. The degradation diagnosis device according to claim 11, wherein the degradation diagnosis device performs a process of extracting the data from the data group for degradation diagnosis.

17. The central processing unit and the storage device are a central processing unit and a storage device of a computer, and the data group includes values of deterioration diagnostic characteristics that change over time, and ultrasonic waves that change in accordance with the values. 17. The degradation diagnosis device according to claim 16, wherein the degradation diagnosis device includes a value of a propagation characteristic and the central processing unit executes a degradation diagnosis program of the following (B).

(B) (1) A procedure for inputting information on the material specifications of the coating layer of the article to be diagnosed,

(2) a procedure for selecting a data group relating to the material of the input specifications from the data group for deterioration diagnosis stored in the storage device;

(3) A procedure for inputting the value of the ultrasonic propagation characteristic obtained by measuring the coating layer of the article, and obtaining the value of the deterioration diagnostic characteristic corresponding to the value from the data group selected in (2), program.

18. The data group for deterioration diagnosis described above includes the type of organic polymer material, the type of plasticizer compounded in the organic polymer material, the compounding amount of plasticizer, the compounding amount of filler, and the force. When the material specification comprising one or more elements selected from the blending amount of one bond is changed, the value of the deterioration diagnosis characteristic for each sample having the different material specification and the value of the ultrasonic transmission characteristic corresponding thereto are changed. 17. The deterioration diagnosis device according to claim 16, which is a data group including the deterioration diagnosis device.